1. Field of the Invention
The present disclosure is related to butterfly valves for aircraft. More particularly, the present disclosure is related to butterfly valves having sleeve inserts.
2. Description of Related Art
In many aircraft, such as those using turbine engines, it is common to use butterfly valves for selectively controlling the flow of high-pressure air to various aircraft systems such as, but not limited to, starting systems, anti-icing systems, electrical generation systems, auxiliary power units (APU's), environmental control systems, and others.
In the use of butterfly valves with starting systems, the high-pressure valve is commonly known as a “starter valve”. The starter valve is used to selectively control the flow of high-pressure fluid to an air turbine starter, which is used to initiate the rotation of the turbine engine. The air turbine starter (ATS) includes a turbine wheel and an output shaft. The starter valve selectively couples the turbine wheel to a high-pressure fluid source such as, but not limited to, air from an auxiliary power unit, bleed air from the compressor stage of an operating gas turbine engine, and other sources. Once the starter valve is opened, the high-pressure air impinges on the turbine wheel, causing the output shaft to rotate. The output shaft, in turn, causes the turbine engine to rotate. Once the turbine engine achieves a desired rotational speed, jet fuel can be ignited within the turbine to start the turbine engine.
In the use of butterfly valves with anti-icing systems, the valves are commonly known as “anti-icing valves”. The anti-icing valve is used to divert a high-temperature fluid source to one or more portions of the aircraft on which ice can form. For example, it is common for anti-icing valves to selectively feed bleed air from the compressor stage of the operating gas turbine engine into an air upstream of the engine's air intake system. The feeding of the high temperature bleed air into and onto various components of the intake system has proven effective at removing ice from these systems.
Thus, it is common to regulate the flow of high pressure, high temperature air (e.g., air from APU and/or turbine engine bleed air) using butterfly valves. However, it has been determined by the present disclosure that the high temperature and pressure of the air can expose the butterfly valves to operating temperatures, pressure, abrasive action, and other conditions sufficient to cause premature valve failure. For example, the high temperature can be sufficient to warp the valve body from a predetermined shape.
In some instances, the warp in the valve body can be sufficient to cause the butterfly flap to rub or scrap against the inside of the valve body, which can cause pits and channels inside the valve body such that the valve leaks even in a closed position. In other instances, the warp in the valve body can be sufficient to prevent the butterfly flap from moving between its open and closed positions.
Accordingly, it has been determined by the present disclosure that there is a continuing need for butterfly valves that overcome, mitigate, and/or alleviate one or more of the deleterious effects of prior art butterfly valves.